nacm BUGFIX nacm extension instances in non-data statements

The nacm extension specifies that in case the nacm extension instance is
in other than data definition node, it is supposed to be ignored, but
the plugin was raising an error and module compilation was stopped.

Instead, let the compilation proceed and generate warning.
diff --git a/tests/utests/extensions/test_nacm.c b/tests/utests/extensions/test_nacm.c
index d8eb157..8d05d1f 100644
--- a/tests/utests/extensions/test_nacm.c
+++ b/tests/utests/extensions/test_nacm.c
@@ -51,15 +51,16 @@
     assert_int_equal(1, *((uint8_t *)e->data)); /* plugin's value for default-deny-all */
     assert_null(cont->next->exts);
 
-    /* invalid */
-    data = "module aa {yang-version 1.1; namespace urn:tests:extensions:nacm:aa; prefix en;"
+    /* ignored - valid with warning */
+    data = "module b {yang-version 1.1; namespace urn:tests:extensions:nacm:b; prefix en;"
             "import ietf-netconf-acm {revision-date 2018-02-14; prefix nacm;}"
             "nacm:default-deny-all;}";
-    assert_int_equal(LY_EVALID, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
+    assert_int_equal(LY_SUCCESS, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
     CHECK_LOG_CTX("Extension plugin \"libyang 2 - NACM, version 1\": "
             "Extension nacm:default-deny-all is allowed only in a data nodes, but it is placed in \"module\" statement.)",
-            "/aa:{extension='nacm:default-deny-all'}");
+            "/b:{extension='nacm:default-deny-all'}");
 
+    /* invalid */
     data = "module aa {yang-version 1.1; namespace urn:tests:extensions:nacm:aa; prefix en;"
             "import ietf-netconf-acm {revision-date 2018-02-14; prefix nacm;}"
             "leaf l { type string; nacm:default-deny-all; nacm:default-deny-write;}}";
@@ -91,17 +92,17 @@
     assert_int_equal(LY_ARRAY_COUNT(leaf->exts), 1); /* NACM extensions inherit */
     assert_ptr_equal(e->def, leaf->exts[0].def);
     assert_int_equal(2, *((uint8_t *)e->data)); /* plugin's value for default-deny-write */
-    assert_null(cont->next->exts);
 
-    /* invalid */
-    data = "module aa {yang-version 1.1; namespace urn:tests:extensions:nacm:aa; prefix en;"
+    /* ignored - valid with warning */
+    data = "module b {yang-version 1.1; namespace urn:tests:extensions:nacm:b; prefix en;"
             "import ietf-netconf-acm {revision-date 2018-02-14; prefix nacm;}"
             "notification notif {nacm:default-deny-write;}}";
-    assert_int_equal(LY_EVALID, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
+    assert_int_equal(LY_SUCCESS, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
     CHECK_LOG_CTX("Extension plugin \"libyang 2 - NACM, version 1\": "
             "Extension nacm:default-deny-write is not allowed in notification statement.)",
-            "/aa:notif/{extension='nacm:default-deny-write'}");
+            "/b:notif/{extension='nacm:default-deny-write'}");
 
+    /* invalid */
     data = "module aa {yang-version 1.1; namespace urn:tests:extensions:nacm:aa; prefix en;"
             "import ietf-netconf-acm {revision-date 2018-02-14; prefix nacm;}"
             "leaf l { type string; nacm:default-deny-write; nacm:default-deny-write;}}";